Shear Behavior of HPC Bulb-Tee Girders

摘要

Three 96-ft (29.3-m) long, 72-in. (1.83-m) deep, pretensioned bulb-tee girders were tested to evaluate behavior under static shear loadings. The three girders had a design concrete compressive strength of 10,000 psi (69.0 MPa) and incorporated 0.6-in. (15.2mm) diameter, Grade 270, low relaxation prestressing strands. One of the girders was designed based on the AASHTO Standard Specifications for Highway Bridges and the other two were designed based on the AASHTO LRFD Bridge Design Specifications. The sheardesigns incorporated the use of eitherwelded wire fabric or conventional bars for reinforcement. Priorto testing, a 10-ft (3.05m) wide reinforced concrete deck slab was added to each girder and a fatigue test was performed. After the fatigue test, each girder was cut in half and both ends were tested to evaluate static shear strength performance. Measured strengths consistently exceeded the design strengths calculated by both AASHTO design approaches using both design and measured material properties.